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Old 05-13-2015, 11:17 PM
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Quote:
Originally Posted by DanSanDiego View Post
Could just a leaking CCV cause the same symptoms (misfire in two cylinders with fuel shutoff)? Because maybe that is all I have wrong. The CEL light was never on previously and the O2 sensors were replaced about 6 months ago.
A leaking CCV is basically a vacuum leak. With a vacuum leak the cylinder will receive a weaker mixture. The weaker mixture will not create as much power as a cylinder with a normal or rich mixture. That is why the computer will assume that it is a misfire. The fuel shutoff is just a way for the computer to prevent damage to the cat converter. Even though the fuel is off, the computer will still provide a signal to the coils to fire the plugs. With no fuel available to cool the cylinder, the heat from the spark plug might had been enough to burn the valve.

Why was the 02 sensor replaced? You need to look at fuel trim readings and 02 voltage readings before assuming 02 sensors are at fault.
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